教學指標(3)

(3)四則運算

手撥眼及腦運算,專注盤算演邏輯,
一個一數曉自然,連加速得推乘法,
續減分完配成商,四則特性知原本,
算式呈現定律通,易位對打樂相長。
   + 1連續數 , -1倒數； +  - 互逆
   1+1+1      = 3 = 1  ×3   , 一有三個
   2+2+2+2 = 8 = 2  ×4   ,  二有四個
☆乘法是加法的速算法
   4  ÷2 = 2  四顆糖平分,每人得二顆
   4 -2 -2 =0 四顆平分減二減二分完
☆除法是減法的速算法
   ∵4+3=7=3+4  ∴4×3=12=3×4
☆∵ 加減互逆 , ∴ 乘除互逆
☆加法適合交換律,乘法也是
   ∵7 -5=2  ≠  5 -7   ∴7÷5  ≠  5÷7
☆減法不適合交換律,除法也相同
☆盤算算盤演證數理邏輯通原本。

(3) four operations

Hand-dial and brain computing, focusing on computing logic,
A number of small nature, and even speed to push the law,
Continued to sub-sub-set into the business, the four characteristics of the original,
The formula is presented with the law.
   + 1 consecutive number, -1 reciprocal; + - reciprocal
   1 + 1 + 1 = 3 = 1 × 3   ,  a three
   2 + 2 + 2 + 2 = 8 = 2 × 4   ,  two have four
☆ multiplication is the addition of the speed algorithm
   4 ÷ 2 = 2 four sugar equal, each person had two
   4 -2 -2 = 0 four cents minus two minus two points finished
☆ division is the speed of the subtraction algorithm
   ∵ 4 + 3 = 7 = 3 + 4 ∴ 4 × 3 = 12 = 3 × 4
☆ ∵ addition and subtraction of each other, ∴ multiplied by the inverse
☆ Addition is suitable for exchange law, multiplication is also
   ∵7 -5 = 2 ≠ 5 -7 ∴ 7 ÷ 5 ≠ 5 ÷ 7
☆ subtraction is not suitable for exchange law, division is also the same
☆ calculate the operator count the logic of the original logic of the original.